Copper or zinc staining is a rapid, sensitive method for detection of protein bands . ~10ng reduced BSA on NuPAGE™ Bis-Tris gels can be detected with both the copper and zinc stain.

Copper Stain: Staining solution - 0.3M CuCl2

After electrophoresis, remove the gel from the cassette and equilibrate the gel in 100 ml of 1X running buffer* for 15 minutes. Immerse the gel in 100 ml of 0.3M CuCl2 solution for about 5 minutes (the protein band will appear as a negative stain with a blue background).

Zinc stain: Staining solution - 0.2 M Imidazole and 10 mM ZnCl2

After electrophoresis, remove the gel from the cassette and equilibrate the gel in 100 ml of 1X running buffer* for 15 minutes. Place the gel in 100 ml of 0.2M Imidazole solution for 10 minutes. Next immerse the gel in 100 ml of 10 mM ZnCl2 solution for about 5 minutes (the protein will appear as a transparent band with a white background).

*The 1X running buffer can be the buffer from the electrophoresis tank after run (MES, MOPS). However, for better contrast of the band, the 1X Tris-Glycine SDS running buffer is recommended.